CN102821457B - Clock synchronizing method based on software defined radio and software defined radio system - Google Patents
Clock synchronizing method based on software defined radio and software defined radio system Download PDFInfo
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Abstract
The invention discloses a clock synchronizing method based on software defined radio in order to overcome the defect that the traditional software defined radio cannot realize networking. The clock synchronizing method based on the software defined radio is used for realizing the synchronization of a clock between at least two software defined radio access points capable of communicating each other and comprises the following steps of: generating a soft clock source in each access point by using software; setting the soft clock source at an optional one access point as a base station soft clock source, and using the soft clock sources of other access points as client end soft clock pre-sources; obtaining a soft clock source offset between a client end and a base station by a return delay algorithm; and adjusting a user end clock source to be synchronized with a base station soft clock source according to the offset. A software defined radio system comprises at least two software defined radio system access points which realize the soft clock source synchronization by using the method. The clock synchronizing method based on the software defined radio and the software defined radio system provided by the invention has the advantages of good flexibility, convenience to use, expandability and easiness in realization of projects.
Description
Technical field
The present invention relates to a kind of clock synchronizing method based on software radio and software radio system.
Background technology
Software radio full name is radio (the Software Defined Radio of software definition, SDR), its core concept is: construct one and have opening, standardization, modular general hardware platform, make A/D and D/A converter as far as possible near antenna, by other various functions, as physical layer and protocol stack etc. are all realized by software.Because of it possess versatility, opening and comprehensively the advantage such as programmability and become solve multiple communication system in wireless communication field and deposit, various Standard Competition is fierce, frequency spectrum resource is nervous and traditional based on hardware, towards the problem such as deficiency preferred of special-purpose custom-built system.
SDR Prototyping Platforms all at present all only achieves communication between points, when adopting multiple spot to build multi-address access network, unified clock is there is not between these access points, Network Synchronization cannot be realized, therefore be difficult to simulate the multiple access access with real-time, as the time division multiple access connecting system of the TDMA characteristics such as GSM, TD-LTE.Net in the wireless communication system of current commercialization synchronous (also referred to as clock synchronous) directly has influence on the success rate of the handover between adjacent base station.
Existing engineered solution has following two kinds: level time second one, directly using computer operating system.All SDR Prototyping Platforms are connected to the Internet (internet) by network interface card, use computer network time protocol (Network Time Protocol, NTP) time synchronized is obtained, then with the granularity division time slot of 10 seconds (or larger), distribute different time slots finally to different SDR platforms.The time slot least unit that the program can reach is level second.Two, a GPS time service receiver is added in all SDR platform front ends.The precision that commercial GPS time service can reach is 10 Microsecond grades.After timing device and gps satellite obtain time synchronized, it constantly notifies SDR physical layer and protocol stack by the form of hard interrupt signal, time slot is divided with the granularity of Millisecond, this and current communication protocol are (as GSM, LTE etc.) match, distribute different time slots then to different SDR platforms, namely can realize the multiple access access of TDMA form.
But the shortcoming of scheme one is: one, adopt the error of time synchronized acquired by NTP comparatively large, two, time slot least unit is level second, can not meet the requirement of the communication protocol of current any one TDMA access way.In general, current time division multiplex protocol requires that time-slot division granularity is at least Millisecond.
The shortcoming of scheme two is: one, GPS can only apply in the spacious environment in outdoor, can not apply in indoor or that wireless environment is more complicated place.Two, GPS is controlled by U.S. government, must weaken the independence of SDR self according to GPS as synchronised clock.Three, the interface difficulty of GPS time service device and SDR software architecture is comparatively large, is unfavorable for research application.Four, adopt hardware clock source to reduce flexibility and the autgmentability of SDR, run in the opposite direction with the core concept such as opening, compatibility of SDR.
Summary of the invention
In order to overcome above-mentioned defect, the invention provides a kind of clock synchronizing method based on software radio realizing Software Radio platform networking.
For achieving the above object, on the one hand, the invention provides a kind of clock synchronizing method based on software radio, for realizing the synchronous of clock between at least two software radio access points, each access point is on a hardware platform and can intercom mutually between each access point, and described method at least comprises the steps:
By Software Create soft clock source in each access point;
Make the soft clock source of any one access point be soft clock source, base station, the soft clock source of other access point is the pre-source of user side soft clock;
Adopt the side-play amount between backhaul time delay algorithm acquisition user side soft clock source and soft clock source, base station;
According to gained side-play amount adjustment user side soft clock source, make it synchronous with soft clock source, base station.
Particularly, at least comprised the steps: by Software Create soft clock source in each access point
Generate a monopolistic thread in the access point, this thread is an exclusive cpu logic core all the time;
The ticktack number of this cpu logic core is extracted in gained thread;
In this exclusivity thread, obtain soft clock source, be the clock accuracy that can reach nanosecond in the CPU of more than 1GHz in dominant frequency.
Particularly, the side-play amount adopting backhaul time delay algorithm to obtain between user side soft clock source and soft clock source, base station at least comprises the steps:
A soft synchronizing sequence is broadcasted every a setting-up time gap in base station;
User side receives described soft synchronizing sequence and decodes, and acquired results after decoding is delivered to media access control layer; User side calculates this soft synchronizing sequence decay time now and obtains side-play amount.
Particularly, the decay time of soft synchronizing sequence at least comprises transmission delay, propagation delay, receive time delay and/or decoding delay.
Particularly, soft synchronizing sequence length is 14 bytes, includes 2 byte packet header, 2 byte duration, 2 byte frame numbers, 2 byte time side-play amounts, 2 byte system information and 4 byte frame check sequence; Wherein, the MAC layer control frame form of WiFi is followed in packet header, and sub type Field Definition is 0000.
Particularly, side-play amount is: TA=(RTD1-RTD2)/2 ≈ T
e+ T
s
Wherein, TA is side-play amount, and RTD1 is that base station end is sent to the time delay received between the soft synchronization sequence signals arrival of response from the soft synchronizing sequence of instruction, and RTD2 is that user side is from receiving soft synchronization sequence signals to indicating the time delay sent between the soft synchronizing sequence of response, T
efor indicated by software instruction soft synchronizing sequence be sent to radio-frequency head antenna really send this soft synchronizing sequence radiofrequency signal between the time interval, T
sthe electromagnetic signal receiving soft synchronizing sequence from antenna for receiving terminal to the physical layer of software radio learn signal arrive time delay.
Particularly, weighted deviation amount is: EstimatedTA=(1-α) × EstimatedTA+ α × CurrentTA
EstimatedTA is the weighted average of TA, measures the CurrentTA weighting obtained obtain by the EstimatedTA of last time and this, and EstimatedTA is by each self-sustaining of each user side and upgrade after setting interval time; Initial value is: EstimatedTA
0=CurrentTA
0.
Particularly, α value is 0.2.
Particularly, T
eat least comprise software processing delay, command time delay and radio-frequency head hardware handles time delay, wherein,
Software processing delay at least comprises the time delay that the redirect of program, function call and code compilation perform;
Command time delay at least comprises instruction is transferred to radio-frequency front-end by hardware platform time delay by USB, serial ports or PCIe.
Particularly, T
sat least comprise that radiofrequency signal to software instruction instruction that radio-frequency head antenna really receives this soft synchronizing sequence receives time interval between soft synchronizing sequence, radio-frequency head completes time delay caused by the time delay of carrier wave and symbol synchronization and signal detection algorithm for the baseband digital signal after down-sampled.
On the other hand, the invention provides a kind of software radio system, comprise at least two software radio access points, each access point is on a hardware platform and can intercom mutually between each access point, realizes the synchronous of soft clock source between described software radio access point by said method.
Particularly, each user side is after making to obtain clock synchronous with base station through backhaul time delay algorithm adjustment local clock, and each time slot of user side aligns with the time slot of base station, and different time slots can be distributed for different user sides in base station; Frame configuration information is included in soft synchronizing sequence, and each user side can according to frame configuring condition, uplink or downlink reception data in the time slot distributing to oneself.
A clock thread exclusive cpu logic core all the time in the soft clock source generation technique that the clock synchronizing method that the present invention is based on software radio proposes, operating system is not allowed to be hung up or dispatch away, this ensure that the requirement of real-time, the precision of nanosecond can be reached simultaneously, also ensure that high-precision requirement.Adopt the frequency of clock during the mode of Software Create clock source adjustable arbitrarily in its precision allowed band, the overhead that routine processes soft clock interrupts is less than I/O to interrupt firmly, and is convenient to the integrated and mutual of SDR, thus overcomes the shortcoming that GPS is difficult to engage.Good flexibility and extensibility, in real time and precision is higher.The complexity of algorithm is less, is easy to Project Realization, possesses higher engineering practicability.
Software radio system of the present invention adopts said method to realize the synchronous of soft clock, overcomes the defect that Current software radio platforms cannot realize networking.Rational in infrastructure, application is convenient, respond well.
Accompanying drawing explanation
Fig. 1 is the false code preferred embodiment generating soft clock source.
Fig. 2 is the soft synchronizing sequence long form of the present invention and explanation of field.
Fig. 3 is backhaul time delay algorithm (RTD) principle schematic.
Fig. 4 is T
e+ T
p+ T
sstatistics histogram.
Fig. 5 is that oscilloscope records soft synchronous effect schematic diagram.
Embodiment
Below in conjunction with Figure of description and preferred embodiment, the present invention is described in detail.
The clock synchronizing method that the present invention is based on software radio is for realizing the synchronous of clock between at least two software radio access points, and each access point is on a hardware platform and can intercom mutually between each access point.The inventive method at least comprises the steps:
By Software Create soft clock source in each access point;
Make the soft clock source of any one access point be soft clock source, base station, the soft clock source of other access point is the pre-source of user side soft clock;
Adopt the side-play amount between backhaul time delay algorithm acquisition user side soft clock source and soft clock source, base station;
According to gained side-play amount adjustment user side soft clock source, make it synchronous with soft clock source, base station.
Wherein, at least comprised the steps: by Software Create soft clock source in each access point
Generate a monopolistic thread in the access point, this thread monopolizes a cpu logic core;
The ticktack number of this cpu logic core is extracted in gained thread;
Be obtain soft clock source in the CPU of more than 1GHz in dominant frequency.
Soft clock source is obtained by generating a clock thread monopolizing a cpu logic core all the time, operating system is not allowed this thread suspension or scheduling to be gone out, ensure that the requirement of real-time, the precision of nanosecond can be reached simultaneously, also ensure that high-precision requirement.
The side-play amount adopting backhaul time delay algorithm to obtain between user side soft clock source and soft clock source, base station at least comprises the steps:
A soft synchronizing sequence is broadcasted every a setting-up time gap in base station;
User side receives soft synchronizing sequence and decodes, and acquired results after decoding is delivered to media access control layer (MAC); The decay time that user side calculates this soft synchronizing sequence obtains side-play amount.
As shown in Figure 3, the core concept of this algorithm is: a soft synchronizing sequence SSS is broadcasted every certain time interval (as 40ms) in base station, user side is successfully receiving this frame and is carrying out being delivered to MAC layer after PHY layer is correctly decoded, Timing Advance (the Time Advanced of terminal clock is determined according to the transmission delay of SSS, propagation delay, receive time delay and/or decoding delay etc., TA), as long as the TA of terminal clock accurately can be determined, so just achieve the clock synchronous between user side and base station.Therefore how to determine that total time delay of SSS from base station to terminal is the key of soft clock simultaneous techniques, consider that transmission delay can only be measured in base station, and user side only can be measured and receives the decode time delay, so all correctly can not estimate total time delay size iff in any one end.
The basic process of RTD algorithm is: first place in the buffer memory of radio-frequency head by after SSS modulating-coding, first base station indicates broadcast transmission one SSS to user side at regular hour node, user side reception and after PHY successfully decodes SSS, indicate transmission one backhaul SSS to base station immediately, base station receives the decode this backhaul SSS again.In Fig. 3, transverse axis represents absolute time (as atomic time or Coordinated Universal Time(UTC) etc.), and the meaning that parameters represents is as follows:
T
e/ T '
e: (Time of Error) represent by software instruction indicate SSS be sent to radio-frequency head antenna really send this SSS radiofrequency signal between the time interval.In general, GPP (General PurposeProcessor) SDR this time upper is approximately several microsecond, and it contains the following aspects:
Software processing delay, the redirect of such as program, the time delay etc. that function call and code compilation perform.
Command time delay, instruction is by USB, and serial ports or PCIe etc. transfer to radio-frequency front-end by PC, and this time delay is Microsecond grade under normal circumstances.
Radio-frequency head hardware handles time delay, the time delay that DSP or FPGA or A/D (D/A) as front end cause, this kind of time delay is prevalent in all communication systems, and is not only confined to SDR Prototyping Platform.
T
p/ T '
p: (Time ofPropagation) represents the spatial time delay between electromagnetic signal BS and UE, and both antenna distances are once determine, so this time delay is also just determined immediately.
T
s/ T '
s: (Time of Sensing signal arriving) represent receiving terminal receives SSS electromagnetic signal from antenna to the physical layer of SDR learn signal arrive time delay.This time delay can be divided into again three part compositions, and one is be similar to T
e/ T '
ethe time delay of inverse process, two is radio-frequency heads for the baseband digital signal after down-sampled completes the time delay of carrier wave and symbol synchronization, and three is the time delays caused by signal detection algorithm, as Autocorrelation Detection algorithm etc.
RTD1: represent that base station end is sent to the time delay size received between the arrival of response SSS signal from instruction SSS, directly can measure from base station end and obtain.
RTD2: representing that user side sends to coming instruction the time delay size responded SSS from receiving SSS signal, directly can be measured by user side and obtaining.
There are two hypotheses in RTD algorithm.First is that trip path in backhaul is identical, that is:
T
P＝T′
P(1)
Second prerequisite is that all SDR platforms all possess identical hardware structure and software architecture, and engineering can obtain:
T
e＝T′
e，T
S＝T′
S(2)
But, even if under ideal conditions, T
eor T
scan not independent measurement obtain accurately.But the time delay between user side and base station is by T
e, T
pand T
sthree's sum obtains, and there is no need the respective size measuring three accurately, and only needs to obtain three's sum:
T
e+T
P+T
S+T′
e+T′
P’T′
S＝RTD1-RTD2 (3)
Simultaneous formula (1), (2) and (3), be not difficult to obtain:
T
e+T
P+T
S＝(RTD1-RTD2)/2 (4)
In the scene of indoor communications, the distance of base station and user side generally within hundred meters, so T
psize be nanosecond, compared to this T
e+ T
sengineering can be similar to and be ignored, so obtain with lower aprons:
TA＝(RTD1-RTD2)/2
≈T
e+T
S(5)
It should be noted that, variable R TD2 contains the decode procedure of physical layer, in SDR Prototyping Platform, owing to being subject to the impact of many factors, there is larger fluctuation in this variable, but this can not have influence on correctness and the robustness of RTD algorithm proposed by the invention, the fluctuation caused by RTD2 is got rid of by the difference of variable R TD1 and RTD2, and this is also the marrow place of difference thought.
Further, in order to ensure that TA had both possessed statistics stability, can reflect again the momentary fluctuation of the supple-settlement time delay of software radio, the present invention have employed the mode of weighted sum further to the estimation of TA:
EstimatedTA＝(1-α)×EstimatedTA+α×CurrentTA (6)
EstimatedTA is a weighted average, measures the CurrentTA weighting obtained obtain by the EstimatedTA of last time and this, and EstimatedTA by each self-sustaining of each user side and at regular intervals (as 40ms) upgrades it.Initial value can make:
EstimatedTA
0＝CurrentTA
0(7)
In the present invention, according to Practical Project test, make α=0.2, make TA both possess statistics stability like this, the momentary fluctuation of the supple-settlement time delay of software radio can be reflected again.
Fig. 4 shows T
e+ T
p+ T
stest result, can be seen by result, average is 16.08us, and mean square deviation is 1.54us2, and the absolute value of maximum/little value and equal value difference is also less than 5us, and this shows T
e+ T
p+ T
sthere is extraordinary statistics stability.See the following form 1.
Table 1.T
e+ T
p+ T
sstatistics.
| Total/times | Mean/us | MSE/us2 | Max/us | Min/us |
| 1000 | 16.08 | 1.54 | 19.07 | 11.45 |
Accompanying drawing 5 is the checkings to RTD correctness of algorithm and error size, obtain the synchronous rear user side of soft clock in user side and base station and also send a SSS at the start node of 40ms, adopt twin-channel digital oscilloscope to measure both antenna radio-frequency signals, result as shown in the figure simultaneously.As can be seen from Figure, user side achieves extraordinary clock synchronous with base station.
This algorithm has taken into full account the processing delay problem of Software Radio platform, compares and encodes or decoding fixed response time situation really with the general baseband chip of commercialization, there is many uncertain supple-settlement time delays in Software Radio platform.This algorithm records the round-trip delay of a SSS and its response SSS respectively in base station and user side two ends, two ends record 1/2 of the difference of different delay and are base station and send the one way time delay that a SSS successfully receives to user side, and base station end is by Time Advanced (TA) field in time delay size write SSS.In order to ensure that TA had both possessed statistics stability, can reflect again the momentary fluctuation of the supple-settlement time delay of software radio, the present invention have employed the mode of weighted sum further to the estimation of TA.Test result shows, the synchronous error of soft clock is less than 10us.
Backhaul Time Delay Estimation Algorithms (RTD) has taken into full account the processing delay problem of Software Radio platform, and the estimation for time delay had both possessed statistics stability, can reflect again the momentary fluctuation of the supple-settlement time delay of software radio.The complexity of algorithm is less, very easily Project Realization, possesses higher engineering practicability.
As shown in Figure 2, the decay time of soft synchronizing sequence at least comprises transmission delay, propagation delay, receive time delay and decoding delay.Soft synchronizing sequence length is 14 bytes, is specifically configured to packet header (frame header, 2 bytes), duration (duration, 2 bytes), system information (system information, 2 bytes), frame number (frame number, 2 bytes), time offset (time advaned, 2 bytes), Frame Check Sequence (FCS:frame check sequence, 4 bytes).The MAC layer control frame form of WiFi is followed in the packet header of soft synchronizing sequence, and sub type Field Definition is wherein 0000, i.e. soft synchronizing sequence.Base station obtains system message field and comprises this cell id and frame configuring condition, and the system message field of user side comprises user ID (UE ID) information.
Software radio system of the present invention comprises at least two software radio access points, each access point is on a hardware platform and can intercom mutually between each access point, realizes the synchronous of soft clock source between software radio access point by method of the present invention.Each user side is after making to obtain clock synchronous with base station through backhaul time delay algorithm adjustment local clock, and each time slot of user side aligns with the time slot of base station, and different time slots can be distributed for different user sides in base station; Frame configuration information is included in soft synchronizing sequence, and each user side can according to frame configuring condition, uplink or downlink reception data in the time slot distributing to oneself.
Preferred embodiment one: based on x86 framework universal PC, operating system is Windows XP (32).First generate the thread of an interrupt class (27 < IRQL < 31), this thread monopolizes the Logic Core of a CPU all the time.In this thread, program all the time continuous extract monopolize the ticktack number of the Logic Core of CPU, the assembly instruction _ rdtsc utilizing intel to provide, can reach the time precision of nanosecond, and false code is as shown in Figure 1.
Achieve high-precision soft clock source in each SDR platform after, choose wherein any one as anolog base station (Base Station, BS), remaining SDR platform is as user side (User Equipment, UE), base station sends a brief soft synchronizing sequence (Software SynchronizationSequence every 40ms, SSS. concrete form is shown in accompanying drawing 2), user side is after successfully decoding obtains soft synchronizing sequence, according to backhaul time delay algorithm (Round-Trip Delay, RTD) time offset (time offset) of local clock and base station clock can be obtained, thus suitably adjust local clock again.
Preferred embodiment two: in operating system be Linux universal PC on, first generate a monopolistic thread, the Logic Core of this thread exclusive CPU all the time.In this thread, program all the time continuous extract monopolize the ticktack number of the Logic Core of CPU, be the time precision that can reach nanosecond in the CPU of more than 1GHz in dominant frequency.
Achieve high-precision soft clock source in each SDR platform after, choose wherein any one as anolog base station (Base Station, BS), remaining SDR platform is as user side (User Equipment, UE), base station sends a brief soft synchronizing sequence (Software SynchronizationSequence every 40ms, SSS. concrete form is shown in accompanying drawing 2), user side is after successfully decoding obtains soft synchronizing sequence, according to backhaul time delay algorithm (Round-Trip Delay, RTD) time offset (time offset) of local clock and base station clock can be obtained, thus suitably adjust local clock again.
The clock synchronizing method that the present invention is based on software radio has good flexibility and extensibility, the frequency of clock is adjustable arbitrarily in its precision allowed band, the overhead that routine processes soft clock interrupts is less than I/O to interrupt firmly, be convenient to the integrated and mutual of SDR, thus overcome GPS be difficult to engage shortcoming.In real time and precision is higher, the requirement of existing business communications system to clock synchronization accuracy is met completely.Backhaul Time Delay Estimation Algorithms obtains the synchronous error of soft clock and is less than 10us (conservative estimation), has met or exceeded the clock synchronization accuracy between present commercial base station completely.Reliable guarantee is provided for time slot (or claiming subframe) the long TDMA time division multiple access connecting system for Millisecond.
Above; be only preferred embodiment of the present invention, but protection scope of the present invention is not limited thereto, is anyly familiar with those skilled in the art in the technical scope that the present invention discloses; the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.Therefore, the protection range that protection scope of the present invention should define with claim is as the criterion.
Claims (9)
1. the clock synchronizing method based on software radio, for realizing the synchronous of clock between at least two software radio access points, each access point is on a hardware platform and can intercom mutually between each access point, and it is characterized in that, described method at least comprises the steps:
By Software Create soft clock source in each access point;
Make the soft clock source of any one access point be soft clock source, base station, the soft clock source of other access point is the pre-source of user side soft clock;
Adopt the side-play amount between backhaul time delay algorithm acquisition user side soft clock source and soft clock source, base station;
According to gained side-play amount adjustment user side soft clock source, make it synchronous with soft clock source, base station;
The side-play amount adopting backhaul time delay algorithm to obtain between user side soft clock source and soft clock source, base station at least comprises the steps:
A soft synchronizing sequence is broadcasted every a setting-up time gap in base station;
User side receives described soft synchronizing sequence and decodes, and acquired results after decoding is delivered to media access control layer; User side calculates this soft synchronizing sequence decay time now and obtains side-play amount;
Side-play amount is: TA=(RTD1-RTD2)/2 ≈ T
e+ T
s
Wherein, TA is side-play amount, and RTD1 is that base station end is sent to the time delay received between the soft synchronization sequence signals arrival of response from the soft synchronizing sequence of instruction, and RTD2 is that user side is from receiving soft synchronization sequence signals to indicating the time delay sent between the soft synchronizing sequence of response, T
efor indicated by software instruction soft synchronizing sequence be sent to radio-frequency head antenna really send this soft synchronizing sequence radiofrequency signal between the time interval, T
sthe electromagnetic signal receiving soft synchronizing sequence from antenna for receiving terminal to the physical layer of software radio learn signal arrive time delay.
2. the clock synchronizing method based on software radio according to claim 1, is characterized in that, is at least comprised the steps: in each access point by Software Create soft clock source
Generate a monopolistic thread in the access point, this thread is an exclusive cpu logic core all the time;
The ticktack number of this cpu logic core is extracted in gained thread;
In this exclusivity thread, obtain soft clock source, be the clock accuracy that can reach nanosecond in the CPU of more than 1GHz in dominant frequency.
3. the clock synchronizing method based on software radio according to claim 1, is characterized in that, the decay time of soft synchronizing sequence at least comprises transmission delay, propagation delay, receive time delay and/or decoding delay.
4. the clock synchronizing method based on software radio according to claim 1, it is characterized in that, soft synchronizing sequence length is 14 bytes, includes 2 byte packet header, 2 byte duration, 2 byte frame numbers, 2 byte time side-play amounts, 2 byte system information and 4 byte frame check sequence; Wherein, the MAC layer control frame form of WiFi is followed in packet header, and sub type Field Definition is 0000.
5. the clock synchronizing method based on software radio according to claim 1, is characterized in that, weighted deviation amount is: EstimatedTA=(1-α) × EstimatedTA+ α × CurrentTA
EstimatedTA is the weighted average of TA, measures the CurrentTA weighting obtained obtain by the EstimatedTA of last time and this, and EstimatedTA is by each self-sustaining of each user side and upgrade after setting interval time; Initial value is: EstimatedTA
0=CurrentTA
0; α value is 0.2.
6. the clock synchronizing method based on software radio according to claim 1, is characterized in that: T
eat least comprise software processing delay, command time delay and radio-frequency head hardware handles time delay, wherein,
Software processing delay at least comprises the time delay that the redirect of program, function call and code compilation perform;
Command time delay at least comprises instruction is transferred to radio-frequency front-end by hardware platform time delay by USB, serial ports or PCIe.
7. the clock synchronizing method based on software radio according to claim 1, is characterized in that: T
sat least comprise that radiofrequency signal to software instruction instruction that radio-frequency head antenna really receives this soft synchronizing sequence receives time interval between soft synchronizing sequence, radio-frequency head completes time delay caused by the time delay of carrier wave and symbol synchronization and signal detection algorithm for the baseband digital signal after down-sampled.
8. a software radio system, comprise at least two software radio access points, each access point is on a hardware platform and can intercom mutually between each access point, it is characterized in that: realize the synchronous of soft clock source by the arbitrary described method of claim 1 to 7 between described software radio access point.
9. software radio system according to claim 8, it is characterized in that: each user side is after making to obtain clock synchronous with base station through backhaul time delay algorithm adjustment local clock, each time slot of user side aligns with the time slot of base station, and different time slots can be distributed for different user sides in base station; Frame configuration information is included in soft synchronizing sequence, and each user side can according to frame configuring condition, uplink or downlink reception data in the time slot distributing to oneself.
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| CN109413679B (en) * | 2017-08-18 | 2021-10-26 | 中国移动通信有限公司研究院 | Time synchronization detection method, device, terminal and computer readable storage medium |
| US10849085B2 (en) | 2017-10-09 | 2020-11-24 | Qualcomm Incorporated | Timing and frame structure in an integrated access backhaul (IAB) network |
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